Phase Change.. need some help..
 

I have been diligently working on my phase change cooling setup now.

I bought a Magic Chef 1.7cu/ft frige. Model # MCBR170B.

I built a resevior inside of the frige.. right under the evaporator/icebox compartment. I filled the resevior up to the very top of the frige.. totally covering all of the evaporator coils.

I was able to take my water down to 1.4F .. This is where I stopped because even though I had anti-freeze in.. it all started to freeze up..

I insulated the entire resevior and all lines.

I placed my water pump in the frige.. under the resevior..

My problem is.. the compressor gets hot.. which is no problem as I found a steady flow of air across the compressor from a fan cools it down quite good.

My problem is that the tops and sides of the frige get quite warm.. even hot.. on the left side.. it gets very hot.

This is due to the condensor being inside of the frige between the outter metal shell and the inner plastic shell.. where all of the blown in insulation is.

My real problem is that my frige can cool the water really cold.. but when I put my 172w peltier in place on my waterblock.. just running the peltier the water temps rise steadily.. on my last test they went from 17F to 40F in an hour or so.

My frige isn't able to cool fast enough..

I believe this is due to the condensors getting so hot.

My plan:

To cut the outter metal shell off.. just over the tops and sides where it gets hot. Then take the blown in insulation away from the condensor. Leaving insulation below the condensor.. but not above it or on it. I will then use a fan to cool it.

How will I do this?

I will use a dremel with a cut off wheel to slowly cut away at the metal. This way I won't puncture the condensor coils.

What I hope to accomplish:

I am hoping that by doing this my frige will be able to work faster.. cooling the liquid faster.

What do you guys think about this? Let me know ASAP because I wanna jump on this and get it done right away.. been working on this project for the past 2 weeks now.

I notice that when the frige is on full power.. and it has to run for a while to get the liquid down cold enough.. the tops and side of the frige get really really hot. The compressor is thermally protected from over heat though.

If you have any questions please ask.. I really want to get this done.. I am looking for ways just to remove the outta shell entirely so I don't have to do blind cutting.

check the wattage on the fridge..


if its less than your peltier, then obviously it wont keep it cool

One other thing..

I read a website were this guy used a 1/20HP compressor.. same as me..

To cool down 2 processors in his server machine. Each processor also had a peltier on it too. He did the same type of setup accept he built his from scratch and kept all parts in his server case.

He achieved VERY cold temps.. He also had 2 120MM fans on the condensor coils.. I believe this is why his setup did so well.

His compressor got to a high temp of 54C.. with out a fan on it.. mine with out a fan on it gets much much hotter then 54C.

The frige uses 130watts of electricity.. I don't know the cooling power though in wattage.

The whole deal is though that it's cooling 2 1/2 gallons of liquid.. that should be plenty enough to keep the peltier cool.. unless the peltier is putting out more then 172w of heat? I don't know how much heat the peltier puts on the hotside when there is just an ambient temp load on the cold side..

I was going to do a live CPU test the other night.. but I got water on my board so I had to let it dry.. I might just try that now.

Tbird 1.4ghz .. I wanna get it to 1.6ghz.. and cool my video card, hard drives, and northbridge with this setup.. it should very well work .. and water temps I should stay below 50F atleast..

It seems like you're doing OK at 40°F if >50°F is you're goal. It seems like the fridge just cant handle the heat. And is this really phase-change? It sounds more like W/C with chilled water.

The water keeps rising.. above 40F.. the last time I did this test it was past 50F... bout 57F and still going up.

Yes this is phase change.. even though I am using it to cool water.. which is more efficient.

OK....I didn't know. Although, it seems like it would be more efficient if you could take the water out of the loop....sorry BAD pun...and cool the CPU directly. Have you tried putting fans on the compressor? What are the heat exchanger pipes cooled by? Maybe put some fans there too.

That's normal. The extra coolant (water?) only acts as a capacitor, i.e. more water does not dissipate more heat.

You really need to strip that fridge apart.

Are you really using water? Doesn't it freeze? What did you add to it? Why on earth would you want to stick your pump in freezing water?

If the fridge uses 130W, that should be an indication of where your problem is. I'm not too familiar with phase change cooling, but there's one physics rule that always applies: no energy is lost, and none is created.

Well I am stripping it down now.. I do believe that a fan on the condensor will solve my problem...

Like I said.. it gets very hot .. and then the heat just sits inbetween the inner frige shell (plastic and outter frige shell (metal)

Welp...

I am ripping the frige apart.. I found out that the condensor is just what I believe to be 1/4" copper tubing.. I know it's flexible copper.. and pretty sure it's 1/4".

Anyway it goes around the sides and top.. so what I am going to do is wind it up around a jar then.. and put 2 fans on each side.. push/pull format.

I am going to basically rip the whole frige apart now.. I have pics and I will post them later if you guys want.

HAHAHAHA AHAHHAH!! GOOD NEWS!!

-15.7F on the evap. coils in half an hour!!

Before.. it would take 2 hours to get down to the single digits on the evap coils..

I totally ripped the frige apart and got the condensor coils out.. now it kicks ass.. I got pics.. I'l put them up soon.

Sweet....lets, see 'em!